Apparatus and process for dividing a nonwoven web

ABSTRACT

An apparatus and process for dividing a nonwoven web into a plurality of ribbons. An assembly of converging ribbons receive and grip the incoming continuous web to create a travel distance differential. One portion of the continuous web is pulled through the assembly of belts at a different velocity than another adjacent portion of the continuous web. Because adjacent portions of the continuous web travel a different distance over a period of time, the orientation of fibers in the web between the two adjacent portions of the web is altered. As the fibers become oriented in the machine direction, the web begins to split into continuous ribbons of desired width.

RELATED APPLICATIONS

[0001] This application claims the benefit of prior copending U.S.Provisional Patent Application Serial No. 60/249,484, filed Nov. 17,2000, entitled “Apparatus and Process for Dividing a Nonwoven Web.”

TECHNICAL FIELD

[0002] The present invention relates to processing a web of fibers intothread and, more particularly, relates to dividing a nonwoven web intomultiple continuous ribbons.

BACKGROUND OF THE INVENTION

[0003] Yam is a strand composed of fibers, filament, or other materials,either natural or man-made, suitable for use in the manufacture offabrics. Most fiber processing operations are performed by mechanicalmeans. Typically, natural fibers such as cotton, or man-made materials,are shipped in bales to a textile mill for yarn manufacturing. Thetraditional processing method involves subjecting the bail of cotton toopening and cleaning, picking, carding, combing, drawing and spinning.

[0004] The cotton bale is opened and its fibers are raked mechanicallyto remove foreign matter. A picker then wraps the fibers into a lap. Acarding machine brushes the loose fibers into rows that are joined as asoft continuous nonwoven sheet, or web, and forms them into looseuntwisted rope known as card sliver. For higher quality yarn, the sliveris put through a combing machine, which strengthens the fibers to afiner degree. In the drawing stage, rollers reduce the sliver to auniform strand of a usable size. The drawing stage is also commonlyreferred to as the drafting stage. Even thinner strands may be producedby pulling and slightly twisting the sliver. Finally, the sliver istransferred to a spinning frame, where it is drawn further, and wound ona bobbin as yarn.

[0005] However, the drawing process to reduce the sliver to a usablesize, and then the pulling on the sliver to reduce the sliver further,are time and space consuming steps of the yarn making process.Eliminating the drawing and the pulling of the sliver would create afaster, more efficient, yarn making process.

[0006] Therefore, there is a need for an apparatus and process fordividing a continuous, nonwoven web from the carding machine into aplurality of continuous ribbons. The present invention must forego thedrawing and pulling of the web into a sliver, but permit the ribbons tobe manufactured according to desired widths with a uniform lineardensity.

SUMMARY OF THE INVENTION

[0007] The present invention solves the above-identified problems byproviding an apparatus and process for dividing a continuous web into aplurality of continuous ribbons. The present invention utilizesdifferences in travel distance of different portions of the continuousweb to achieve fiber parallelization and repetition. The difference intravel distance between portions of the continuous web is achieved bycreating a velocity differential between adjacent portions of the webover a fixed period of time.

[0008] Generally described, the present invention includes an apparatusfor providing a plurality of continuous ribbons from a continuousnonwoven web. The apparatus includes an assembly of converging belts. Atleast two pairs of converging belts lie longitudinally adjacent to oneanother. Each pair of converging belts cooperate to receive and grip theincoming continuous web. At least one pair of converging belts variesthe speed of one portion of the continuous web relative to anotheradjacent portion of the continuous web driven by the other pair ofconverging belts. Because adjacent portions of the continuous web aredriven at different speeds, the continuous web is divided in alongitudinal manner into two continuous ribbons of desired width.

[0009] According to one aspect of the invention, a wheel sized tofacilitate shearing engages and places pressure on each pair ofconverging belts. Because the belts are then urged against thecontinuous web, the continuous web is gripped by the belts.

[0010] According to another aspect of the invention, a pair of pressurepads persuades a pair of converging belts against the continuous web.The pressure pads are laterally spaced from one another andsubstantially coextensive. The pressure pads are moveable with respectto one another to permit the pair of belts to pass therebetween.

[0011] The foregoing has broadly outlined some of the more pertinentaspects and features of the present invention. These should be construedto be merely illustrative of some of the more prominent features andapplications of the invention. Other beneficial results can be obtainedby applying the disclosed information in a different manner or bymodifying the disclosed embodiments. Accordingly, other aspects and amore comprehensive understanding of the invention may be obtained byreferring to the detailed description of the exemplary embodiments takenin conjunction with the accompanying drawings, in addition to the scopeof the invention defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 illustrates the orientation of fibers in a portion of acontinuous nonwoven web as it moves through the present invention.

[0013]FIG. 2 illustrates a top view of one embodiment of the presentinvention having two synchronized pairs of converging belts forreceiving the continuous nonwoven web.

[0014]FIG. 3 is a perspective view of a plurality of continuous ribbonsderived from the continuous web of FIG. 1.

[0015]FIG. 4 is a side view of one embodiment of one pair of convergingbelts adapted to be urged against the incoming continuous web by a pairof pressure pads.

[0016]FIG. 5 illustrates an alternative embodiment of the presentinvention having a plurality of rollers persuading the converging beltsagainst the incoming continuous web.

[0017]FIG. 6 illustrates an alternative embodiment where the pair ofconverging belts are persuaded against the continuous web by anoversized wheel.

[0018]FIG. 7 illustrates an alternative configuration of the presentinvention utilizing the oversized wheel.

[0019]FIGS. 8 and 9 illustrate alternative pulley configurations of thepresent invention.

[0020]FIG. 10 illustrates a cross-sectional view taken along the lineA-A of FIG. 2.

[0021]FIG. 11 illustrates a cross-sectional view taken along the lineB-B of FIG. 2.

[0022]FIG. 12 illustrates a cross-sectional view taken along the lineC-C of FIG. 2.

[0023]FIG. 13 illustrates a cross-sectional view taken along the lineD-D of FIG. 10.

[0024]FIG. 14 illustrates a cross-sectional view taken along the lineE-E of FIG. 10.

[0025] Similar reference characters refer to similar parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

[0026] Referring now to the drawings in which like numerals indicatelike elements throughout the several views, FIG. 1 illustrates anexemplary embodiment of the general operation of splitting a continuousnonwoven web 10 into continuous ribbons 12, 14 and 16. While aparticular embodiment of the present invention may be described withreference to a particular number of continuous ribbons, it is understoodthat the present invention may be adapted to split the continuous web 10into any number of continuous ribbons.

[0027] In FIG. 1, the nonwoven web is made up of a mass of fibers suchas in cotton or polyester. As a result of altering the orientation ofthe fiber along lines 20 and 22, the web 10 is split along lines 20 and22. A typical fiber spanning the space between the adjacent ribbons willgradually be pulled in the longitudinal direction until it breaks or ispulled loose from one of the ribbons. A plurality of fibers 24 isillustrated along line 22. The line 22 defines the split betweenadjacent continuous ribbons 14 and 16. The fibers 24 on the left side ofline 22, where the web 10 is only beginning to split, are orientedsubstantially in an transverse manner relative to the machine directionof the web 10. However, as the fibers 24 become more longitudinallyoriented, in the machine direction, the web 10 begins to split along theline 22. The portion of FIG. 1 having reference number 24 could also beused to visualize the orientation of a single fiber as it progressesthrough the process to achieve fiber parallelization.

[0028] As shown generally in FIG. 2, the present invention includes anassembly of converging belts for receiving a continuous web at avelocity V₁. The assembly of belts includes at least two pair ofconverging belts for gripping the continuous web 10. For example, thebelts are flat belts obtained from Habasit Belting, Inc. The surfaces ofthe belts may be smooth, textured or otherwise formed to enhance thegrip on the web 10. The belts may also be coated with a substance suchas Teflon® to achieve the desired surface.

[0029] A portion of one belt of a pair of converging belts iscoextensive with a portion of the other corresponding belt of the pairof converging belts (FIG. 4). Preferably, the coextensive portions ofeach pair of belts are vertically opposed to one another. The length ofthe coextensive portion for gripping the web 10 is dependent on thevelocity desired for the ribbons. A longer coextensive portion onlyneeds a smaller speed differential because a longer distance is traveledin order to split the web 10. For example, a 2 inch differential, whichis not a large differential, could occur over a 50 inch travel. As bestshown in FIG. 2, each pair of converging belts is placed along side oneanother to align the coextensive portions in the machine direction forthe entire width of incoming continuous web. Moreover, the widths of theresulting continuous ribbons depends on the width of each pair ofconverging belts.

[0030] One pair of converging belts grips a portion of the incomingcontinuous web and the other pairs grip another portion of thecontinuous web. Each pair of converging belts is driven at a velocitydifferent from the immediately adjacent pair of converging belts.Preferably, the relative speeds are varied by approximately 4% to 10%.However, the determining factors are machine dimension dependent. Forexample, a 10% speed differential may be obtained by a smaller wheelcompared to a 4% speed differential obtained from a larger wheel and, ineither case, the desired travel distance differential would be the same.Preferably, the travel distance differential is approximately the fiberlength.

[0031] In FIGS. 1 and 2, for example, the portions of the web 10resulting in ribbons 12 and 16 are driven at V₂ whereas the portionresulting in ribbon 14 is driven at V₃. The velocity differentialresults in a differential draft. FIG. 3 illustrates in particular theribbons 12, 14 and 16 being driven at their respective velocities. Thespeed of all ribbons should exceed the speed of the web 10 to maintainthe appropriate tension in the web 10 and to cause a small amount ofdrafting. For example, V₂ is preferably 20% faster than V₁. Because twoadjacent portions are pulled at a different velocity, the continuous webis split into two continuous ribbons. Although FIG. 2 illustrates a topview of these pair of converging belts for producing three continuousribbons, the number of continuous ribbons derived from the continuousweb depends on the number of pairs of converging belts and the number ofvelocity differentials created between adjacent portions of thecontinuous web.

[0032] Because the present invention utilizes differences in speed tocreate a travel distance differential, the ribbons may all be drivenfrom the apparatus in the same direction. FIG. 3 further illustrates theribbons 12, 14 and 16 being dispersed in the horizontal direction asillustrated by directional arrow 30. Preferably, there is no verticalvelocity placed on the web 10 so that the ribbons 13, 14 and 16 maycontinue in a horizontal manner to be collected in yarn spinning headsor other drafting apparatus.

[0033] Referring now to FIGS. 2 and 4, the present invention includes aplurality of shafts, gears and pulleys for driving the assembly ofconverging belts. However, various combinations of shafts, gears,pulleys or other devices may be utilized to maintain the desired belttension and guidance. The upper and lower belts in each pair ofconverging belts are synchronized to have a ratio of 1:1. Therefore, theupper and lower shafts driving a pair of converging belts rotate at thesame speed. In the embodiment shown in FIG. 2, upper shafts 32 and 34and are supported by pillow block bearings 36. The upper belts aresupported on pulleys on the upper shafts 32 and 34. In FIG. 2, sprockets38 are connected to one end of shafts 32 and 34. A pair of timing belts(not shown) are then connected between driver motors and the sprockets38. FIG. 4 best illustrates lower shafts 40 and 42 synchronized withupper shafts 32 and 34, respectively.

[0034] In FIG. 2, the shafts 32 and 34 are supporting three pair ofconverging belts 44, 46 and 48. Each pair of belts may be similar orvaried in widths to produce ribbons of similar or varied widths. FIGS.4-12 are side views of various embodiments of the present inventionwhich best illustrate an upper belt and a lower belt for each pair ofconverging belts. In FIG. 2, shaft 32 drives the upper belts of the pairof converging belts 44 and 48 at the velocity V₂ which is greater thanV₁. The pulley on shaft 32 for the upper belt of the pair of convergingbelts 46 is an idler that turns freely on shaft 32. Shaft 34 drives theupper belt of the pair of converging belts 46 and the pulleys on shaft34 for the upper belts of the pairs of converging belts 44 and 48 areidlers that turn freely on shaft 34. In FIGS. 4 and 5, pulleys 50 onshafts 32 and 34 support the upper belts 44 a, 46 a and 48 a and pulleys50 on shafts 40 and 42 support lower belts 44 b, 46 b and 48 b. In someembodiments, spacers may be used between adjacent pulleys or rollers toprevent belt wobble. Alternatively, one or more of the pulleys and/orrollers may be flanged. The flanged portion may be as tall as the widthof the belts.

[0035] In the present invention, a pair of drivers may be used to drivethe driver shafts. Each of the drivers may be operated separately tocreate and maintain the spread differential. However, because offriction, it may be preferable to start one driver and obtain onedesired speed and then start the second driver; but then slowly increasethe speed generated by the second driver to minimize friction. Also, inanother alternative embodiment, a single positive differential driverwith increased horsepower may be used. A single belt and differentlysized sprockets may be used in conjunction with the single driver tocreate the speed differential while still minimizing friction.

[0036] Still referring to FIG. 4, one embodiment of the presentinvention includes at least one pair of pressure pads 54. Preferably,one pair of pressure pads 54 correspond with one pair of convergingbelts. The pressure pads 54 provide a gripping force on the belts forconstraining portions of the web 10 which result in the ribbons.

[0037] As shown in FIG. 4, the pressure pads 54 are laterally spacedfrom one another and substantially coextensive. Also, the pressure pads54 are preferably elongated and vertically opposed to each other. Eachpair of pressure pads 54 cooperate to permit the upper and lower beltsof one pair of belts to pass therebetween. In other words, the pressurepads are moveable with respect to each other from a spaced clearanceposition into a contact position relative to the belts passingtherebetween. In the contact position, the pair of pressure pads 54 urgethe pair of belts against the continuous web 10.

[0038] In FIG. 5, the pressure pads 54 are replaced with a plurality offreely turning rollers 51 to urge the pair of belts against thecontinuous web. Preferably, the rollers 51 are evenly spaced along thelength of the coextensive portion of each pair of converging belts.However, the upper rollers 51 are offset from the lower rollers 51.

[0039] In other alternative embodiments, shown in FIGS. 6-10, thepresent invention includes an oversized wheel 56 in place of the rollers51 and pressure pads 54 which creates less friction compared to therollers 51 and pressure pads 54. The wheel 56 is oversized relative tothe size of a single pulley 50 or roller 51. The wheel 56 is configuredto engage and place pressure on at least one pair of converging belts.Belt tension is used against the wheel 56 to provide the desiredgripping force applied to the respective ribbons. By placing pressure onthe pair of converging belts, the pair of converging belts are urgedagainst the continuous web. Preferably, the wheel 56 is sized relativeto the length of the coextensive portion of a corresponding pair ofconverging belts such that griping force with the continuous web 10 ismaximized. In other words, a large wheel 56 is desired in order toachieve a longer grip length. A diameter of approximately 20 inches forthe wheel 56 is believed to be suitable for use with most known cardingmachines.

[0040] In FIG. 6, the pair of belts 44, 46 and 48 are supported on anassembly of pulleys 50 which are, in turn, carried by shafts 32, 34, 40,42, 62 and 66. The wheel 56 is supported by shaft 60 and is permitted tofreely rotate about shaft 60. Note that the shafts 40 and 42 arepositioned above the shaft 60. In this embodiment, the web 10 isreceived from the left and passes over the pulleys 50 on shaft 40. Atthis point, the web 10 is only in contact with the lower belts 44 b, 46b and 48 b. However, as the web 10 continues to pass over the pulleys ofshaft 40, the web 10 is received between the lower belts and the upperbelts upon the wheels 56. The web 10 remains between the pair of beltswhile traveling below a horizontal plane through the axis of rotation ofshaft 60. In other words, the web 10 is positioned between thecoextensive portion of belts on the lower half of the wheels 56.However, shaft 34 is positioned approximately above shaft 42. Thispermits the web 10 to remain between the belts until the web 10 passesthrough a vertical plane intersecting the axis of rotation for theshafts 34 and 42 where the belts are no longer coextensive. Otherconfigurations may be used to maintain the pair of converging belts 44,46 and 48 upon a portion of their respective wheels 56.

[0041] In FIGS. 7-10, various other configurations of shafts and pulleysare demonstrated for use with wheels 56. The embodiment shown in FIG. 7,however, utilizes a set of three axially aligned wheels 56 that eachpreferably include cording pins (not shown) that will grip the web 10and release the ribbons. Also, in FIG. 7, the wheels 56 rotate freelyabout shaft 60. Shaft 62 drives pulleys 50 for the lower belts 44 b and48 b and, therefore, the two corresponding wheels 56. Shaft 66 drivespulley 50 which drives the lower belt 46 b and, therefore, the middlewheel 56. Preferably, all three wheels 56 are grooved at theircenterlines to receive and retain their respective belts.

[0042]FIG. 8 illustrates an embodiment which includes only upperconverging belts 42 a, 44 a and 46 a and no other belts. In anembodiment such as this, a single set of belts converges against a body,such as the wheel 56. Alternatively, the body against which the singleset of belts converge against may be a plurality of rollers or pressurepads as described above. FIG. 9 illustrates the same embodiment as shownin FIG. 8 except the configuration of belts is inverted. FIGS. 8 and 9further include shafts 33 and 41, respectively, to further support thebelts. The embodiments shown in FIGS. 8 and 9 are preferably utilizedwith the wheels 56 having an elastomer or fabric surface.

[0043]FIG. 10 illustrates a cross-sectional view taken along the lineA-A of FIG. 2 and FIG. 11 illustrates a cross-sectional view taken alongthe line B-B of FIG. 2. FIG. 10 illustrates in particular a side view ofthe pair of belts 42 a-b, 44 a-b and 46 a-b and the shafts 32, 34, 40,42, 60, 62 and 66 in combination with the wheels 56. The preferredarrangement of the gears 28 are best illustrated in FIG. 11.

[0044]FIG. 12 illustrates a cross-sectional view taken along the lineC-C of FIG. 2 and best illustrates adjustable speed motors 70 fordriving shafts 32 and 34. The motors are coupled to the ends of theshafts 32 and 34. In this embodiment, the motors 70 are supported byframe member 72.

[0045]FIG. 13 illustrates a cross-sectional view taken along the lineD-D of FIG. 10 and FIG. 14 illustrates a cross-sectional view takenalong the line E-E of FIG. 10. As shown in FIGS. 13 and 14, keys 66 fixthe two outer pulleys 50 to the shaft 32 in order to drive the belts 42a and 44 a. The center pulley corresponding with the upper belt 44 a isan idler. FIG. 14 illustrates the shaft 34 secured to the center pulleywith a key 66. Keys 66 are also utilized to secure the sprocket 38 tothe shaft 32 as shown in FIG. 13.

[0046] The present invention may also include an aspirator, vacuum, airmover or other device for generating an air flow to facilitate theseparation of the ribbons 12, 14 and 16 from the belts of the presentinvention. The air may be supplied just prior to or immediately afterthe ribbons exit from between the converging belts. Alternatively, or inaddition, a take-up roll may be used to take up each of the ribbons 12,14 and 16 to prevent the ribbons 12, 14 and 16 from sticking to thebelts and becoming caught.

[0047] The present invention has been illustrated in relation toparticular embodiments which are intended in all respects to beillustrative rather than restrictive. Those skilled in the art willrecognize that the present invention is capable of many modificationsand variations without departing from the scope of the invention.Accordingly, the scope of the present invention is described by theclaims appended hereto and supported by the foregoing.

What is claimed is:
 1. An apparatus for providing a plurality of ribbonsfor a continuous nonwoven web, said apparatus comprising a firstassembly of belts converging toward an assembly of corresponding bodies,said belts and said bodies cooperating to receive and grip thecontinuous web therebetween, and one of said belts cooperating with oneof said bodies adapted to vary the travel distance during a period oftime of one portion of the continuous web relative to another adjacentportion of the continuous web to define a travel distance differentialsuch that the continuous web is divided in a longitudinal manner intosaid portions of the continuous web.
 2. The apparatus of claim 1 whereinsaid travel distance differential is created by varying the velocity ofone of said portions of the continuous web relative to another portionof the continuous web.
 3. The apparatus of claim 1 wherein said traveldistance differential is approximately equal to the length of a fiber ofthe continuous web.
 4. The apparatus of claim 1 wherein said body is asecond assembly of belts cooperating with said first assembly of belts.5. The apparatus of claim 1 wherein said body is a pressure pad.
 6. Theapparatus of claim 1 wherein said body is a plurality of rollers.
 7. Theapparatus of claim 1 wherein said body is a rotatable wheel.
 8. Anapparatus for providing a plurality of ribbons from a continuousnonwoven web, said apparatus comprising an assembly of converging belts,said assembly of converging belts comprising at least two pair ofconverging belts, each said pair of converging belts longitudinallyadjacent to one another, each said belt of said pair of converging beltscooperating to receive and grip the continuous web therebetween, atleast one of said pair of converging belts adapted to vary the speed ofone portion of the continuous web relative to another portion of thecontinuous web such that adjacent portions of the continuous web travela different distance during a period of time, thereby dividing thecontinuous web in a longitudinal manner into at least two continuousribbons of desired width.
 9. The apparatus of claim 8 further comprisinga pulley assembly for each said belt of said pair of converging belts.10. The apparatus of claim 8 wherein each of said converging belts areurged against the continuous web.
 11. The apparatus of claim 8 furthercomprising a wheel configured to urge at least one of said pair ofconverging belts against the continuous web.
 12. The apparatus of claim11 wherein said wheel is sized relative to the coextensive length ofeach said pair of belts such that the contact with the continuous web ismaximized.
 13. The apparatus of claim 8 further comprising a pair ofpressure pads, said pressure pads laterally spaced from one another andsubstantially coextensive, said pair of pressure pads cooperating topermit one of said pairs of belts to pass therebetween and to urge saidone of said pair of belts against the continuous web.
 14. The apparatusof claim 13 wherein said pressure pads are moveable with respect to eachother from a spaced clearance position into a contact position relativeto said belts.
 15. The apparatus of claim 13 wherein said pressure padsare elongated and vertically opposed to each other.
 16. The apparatus ofclaim 8 further comprising a plurality of rollers cooperating to permitone of said pair of belts to pass therebetween and to urge said one ofsaid pair of belts against the continuous web.
 17. The apparatus ofclaim 8 wherein the difference in speed between adjacent pairs ofconverging belts is in the range of approximately 4% to 10%.
 18. Aplurality of continuous ribbons configured from a continuous nonwovenweb, a first portion of said continuous web having been driven at afirst velocity and an adjacent second portion of said continuous webhaving been driven at a second velocity such that said continuous webdivides between said first and second portions, thereby defining saidplurality of continuous ribbons.
 19. A method for providing a pluralityof ribbons from a continuous nonwoven web, said method comprising thesteps of: receiving the continuous web in an assembly of convergingbelts; gripping the continuous web in said assembly of converging belts;varying the travel distance during a period of time of a first portionof the continuous web with said assembly of converging belts relative toa second portion of the continuous web; and in response to said traveldistance varying step, dividing the continuous web in a longitudinalmanner between said first and second portions of the continuous web intoa plurality of continuous ribbons of desired width.
 20. The method ofclaim 19 wherein each said portions of the continuous web are free ofvertical velocity.
 21. The method of claim 19 further comprising thestep of dispersing said plurality of continuous ribbons in substantiallythe same direction.
 22. The method of claim 21 wherein said plurality ofribbons are dispersed in substantially a horizontal manner.
 23. Themethod of claim 19 wherein said gripping step comprises passing thecontinuous web between a pair of converging belts of said assembly ofconverging belts.
 24. The method of claim 19 further comprising the stepof collecting said plurality of continuous ribbons in yarn spinningheads.
 25. The method of claim 19 wherein said gripping step comprisespassing said first portion of said continuous web through a first pairof converging belts of said assembly of converging belts and said secondportion of said continuous web through a second pair of converging beltsof said assembly of converging belts adjacent to said first pair ofconverging belts.
 26. The method of claim 25 wherein said gripping stepfurther comprises applying pressure upon said pairs of belts such thatsaid belts are urged against the continuous web.
 27. The method of claim19 wherein said step of varying the travel distance is achieved bycreating a speed differential between said first and second portions ofthe continuous web.
 28. A plurality of ribbons produced in accordancewith the process of claim
 19. 29. An apparatus for providing a pluralityof ribbons from a continuous nonwoven web, said apparatus comprising:means for driving a first portion of the continuous web at a firstvelocity; and means for driving a second portion of the continuous webat a second velocity, thereby creating a travel distance differential toselect the continuous web in a longitudinal manner into said first andsecond portions to define two continuous ribbons of desired width.